As an input/output interface of an information processing apparatus, there is, for example, a touch panel device which displays various operation sections by display switching, and which enables a predetermined operation input by touching the displayed operation sections. Recently, this type of touch panel device is often installed in a mobile phone. The touch panel is used as a display screen, and is also used as the operation sections. This improves usability while increasing the size of the display screen with the advancement of multifunction.
However, in the information processing apparatus having the touch panel installed therein, an operator may unintentionally touch the operation sections displayed on the touch panel, causing an erroneous operation. For example, the mobile phone is brought near the face during talk, and therefore, the body such as the face may come in contact with the touch panel. In that occasion, there arises the problem that the unnecessary operation button is unintentionally operated in the middle of the talk, causing an erroneous operation. Also in the information processing apparatus having the touch installed therein, the operation is performed on the screen where key positions are unfixed. Therefore, upon receipt of an incoming phone call during the touch panel operation, the display screen is changed into an incoming phone call screen and, at the same time, an unintentional situation may occur during an input operation. As the result, the operator might reply to the incoming phone call by an erroneous operation.
Regarding the above problem, in the communication terminal device disclosed in patent document 1, in order to prevent the erroneous operation during talk, an input enabled range to enable input during talk is set to a part of a touch panel. Therefore, no input is enabled except for the input enabled range during talk, thereby suppressing the erroneous operation.
Patent documents 2 and 3 disclose phone terminals having a touch panel installed therein which is adapted to uniformly avoid the operator's erroneous operation by nullifying the operator's operation during a predetermined period of time, when an incoming phone call occurs.
Patent document 1: Japanese Unexamined Patent Application Publication No. 2000-349886
Patent document 2: Japanese Unexamined Patent Application Publication No. 2005-203930
Patent document 3: Japanese Unexamined Patent Application Publication No. 2007-235676